As a circuit that converts an analog signal into a digital signal, an analog-digital converter (also referred to as an AD converter) is used. For the conventional AD converter, successive approximation or the like has been employed (e.g., Patent Document 1).
As an example of an electronic circuit including an AD converter, there is a digitally-controlled power supply circuit. As a power supply circuit, for example, a circuit that converts a given DC voltage into another DC voltage (also referred to as a direct current-direct current converter or a DC-DC converter) is given.
The DC-DC converter includes, for example, a coil, a diode, a transistor, and the like (e.g., Patent Document 2).